Product number: NCM0021

Xylose Lysine Deoxycholate (XLD) Agar (ISO) is a selective agar for the detection of Salmonella spp. in food, animal feed and in environmental samples from the food production area as described in ISO 6579-1:2017. Xylose Lysine Deoxycholate (XLD) Agar (ISO) is not intended for use in the diagnosis of disease or other conditions in humans.

A selective, diagnostic agar for the detection of Salmonella spp. in food, animal feed and in environmental samples from the food production area as described in ISO 6579-1:2017. Originally formulated by Taylor to differentiate enteric pathogens, the agar is widely used as the preferred differential medium for Salmonella spp. The medium is void of peptones but instead uses yeast extract as a carbon, nitrogen and vitamin source and xylose, lactose and sucrose are fermentable carbohydrates. Salmonella are able to ferment xylose to produce acid but not lactose or sucrose. When the xylose is exhausted Salmonella will decarboxylate lysine shifting the pH back to neutral. At near neutral pH, Salmonella can reduce sodium thiosulfate producing hydrogen sulfide which creates a complex with ferric ammonium citrate to produce black or black centred colonies. Other organisms are able decarboxylate lysine but acid production from the fermentation of lactose and sucrose keeps the pH too acidic for H2S production. Selectivity is achieved through the incorporation of sodium deoxycholate and phenol red acts as a pH indicator. According to ISO 6579-1:2017, subculture is performed separately from both Rappaport-Vassiliadis medium with Soya (RVS) and Muller-Kauffmann tetrathionate-novobiocin (MKTTn) broth. This medium conforms to the performance and formulation requirements of ISO 6579-1:2017.


Formula Liter
Yeast Extract 3.0 g/L
Sodium Chloride 5.0 g/L
Xylose 3.75 g/L
Lactose 7.5 g/L
Sucrose 7.5 g/L
L-Lysine Hydrochloride 5.0 g/L
Sodium Thiosulfate 6.8 g/L
Ferric Ammonium Citrate 0.8 g/L
Phenol Red 0.08 g/L
Sodium Deoxycholate 1.0 g/L
Agar 13.0 g/L

Final pH: 7.4 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 53.5 grams of the medium in one liter of purified water.
  2. Bring rapidly to the boil with frequent stirring, and immediately transfer to a 45-50°C water bath. DO NOT OVERHEAT.
  3. Pour into plates as soon as the medium has cooled.
  4. Protracted boiling or prolonged holding at elevated temperature induces precipitation.

Product was previously known as Acumedia Product: 9207 Xylose Lysine Deoxycholate (XLD) Agar (ISO); and LabM Product: LAB032 XLD Agar

Order Details

Product # Product Description
NCM0021A Xylose Lysine Deoxycholate (XLD) Agar (ISO), 500 g
NCM0021B Xylose Lysine Deoxycholate (XLD) Agar (ISO), 5 kg
NCM0021C Xylose Lysine Deoxycholate (XLD) Agar (ISO), 10 kg
NCM0021D Xylose Lysine Deoxycholate (XLD) Agar (ISO), 25 kg (European only size)
NCM0021E Xylose Lysine Deoxycholate (XLD) Agar (ISO), 50 kg (US only size)

This product is also available with a CE mark but with restricted sales geographically. Please click here for product details.

Reference Material

NCM0021 - Xylose Lysine Deoxycholate (XLD) Agar (ISO), Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]
NCM0021 - Xylose Lysine Deoxycholate (XLD) Agar (ISO), Technical Specifications Sheet [English]

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